Cold forming lubricant and method of applying same



United States Patent 3,042,558 CGLD FQRMING LUBRICANT AND NETHGD 0F APPLYHJG SAME William L. Kubie, Peoria, Ili., assignor to Aluminum Research Corporation, Wilmington, Del., a corporation of Delaware No Drawing. Filed May 28, 1959, Ser. No. 816,389

10 Claims. (Ci. 148--6.14)

This invention relates to lubricants to be used on metals during the cold forming thereof and particularly to such lubricants used in the cold extrusion of metals.

In the cold extrusion of relatively malleable metals such as, for example, aluminum, magnesium, copper and other alloys, the reduction and surface ratios attainable is dependent upon the efficiency of the lubricating layer existing between the metal billet and the die surface.

The term reduction and surface ratios refers to the ratio of the cross-sectional areas and the ratio of the surface areas of the metal article after extrusion to the corresponding dimensions of the original metal billet.

Many standard lubricants, such as petroleum oil and greases, may be used to achieve small reduction and surface ratios, i.e., ratios of from 2:1 to 3:1. This is particularly true when the cross-sectional area of the metal billet, that is, the metal article prior to extrusion, is small. When these ratios approach or exceed 5 to l and the cross-sectional area of the metal billet is increased, conventional lubricants break down and fail under the heat and shearing forces occurring during extrusion. In order to achieve higher reduction and surfac ratios, efforts have been made to develop new lubricants suitable for use under the conditions found in extrusion. An example of such lubricants are those having a phosphat base. The complex and metastable nature of the phosphate base lubricants makes reproducibility difiicult and the lubricant is frequently marginal if not unsatisfactory. In addition, the use of such phosphate lubricants adversely affects the surface finish of the extruded metal, For example, extruded aluminum tubing to which phosphate base lubricants have been applied has a dull, cloudy and uneven surface finish. As the reduction and surface ratios are increased above approximately 7 :1 and the cross-sectional area of the metal billet is increased, the efiiciency of the phosphate lubricant decreases. As a result of lubricant failure, the extruded metal adheres or even becomes welded to the die or tooling, causes excessive wear on the die or tends to cause stick-slip extrusion, giving the resulting extruded product a nonuniform cross-section.

Accordingly, one of the principal objects of the present invention is to provide a lubricant suitable for use in the cold forming of metals which overcomes the above disadvantages.

A further object of the present invention is to provide a lubricant which will allow metals to be extruded at low temperatures and at high reduction and high surface ratios.

A further object of this invention is to provide a lubricant capable of strong bonding to metals and suitable for use at high pressures and high surface temperatures.

A further object is to provide a lubricant which may be applied to a metal billet in a uniform and controllable manner.

A further object of this invention is to provide a method for applying a cold extrusion lubricant to a metal billet.

Still another object of this invention is to provide a metal billet suitably lubricated for use in the cold extrusion process.

Other objects and advantages of this invention will be apparent from the following detailed description.

Generally, the lubricant, which is th subject of the present invention, is in the form of an emulsion and comprises a mixture of a lubricating agent such as a fatty acid, soap or ester thereof and a carboxylic polymthylene polymer in a selected solvent For the purpose of this specification, the term lubrieating agent will refer to materials such as the fatty acid or derivatives thereof indicated above, and the term reactant will apply to the carboxylic polymethylene or other ingredient capable of reacting with the metal which is to be extruded or otherwise deformed.

In order to achieve satisfactory lubrication at high reduction and surface expansion ratios, i.e., 5:1 or more, it is essential that the lubricant adheres firmly to the metal billet, that it maintains its presence on the expanding surface under the conditions found in the cold extrusion or other deformation process and that it improves, or at least does not adversely affect, the surface finish of the completed article. For the purposes of this specification the terms cold forming and cold extrusion refer to the working of a metal at temperatures below its recrystallization temperature and include such processes as cold rolling, deep drawing and wire drawing in addition to extrusion.

Fatty acids and their esters and metallic soaps, are well known lubricants. However, under the conditions of cold extrusion such compounds are not sufficient by themselves to give satisfactory lubrication. It has now been determined that by the use of a composition including a reactant, a chemical bond is formed resulting in strong adhesion of the lubricant to the surface of the metal billet. The exact nature of this bond is not completely understood. However, it appears likely that under the conditions of the process of applying the lubricant as discussed below, part of the metallic surface is converted to integrally held molecules having lubricant properties or capable of forming strong bonds with lubricant molecules.

Thus, the process of applying the lubricating compositions in accordance with this invention results in the combination of surface atoms of the metal billet with long chain negative radicals, thus forming a surface layer which is strongly bonded to the metal of the billet and which has lubricating properties. This surface layer also exerts attractive forces toward other lubricant molecules present in the composition used in coating the billet.

Because of the chemical as distinguished from the physical nature of the bonding of the lubricant to the billet, reduction and surface expansion ratios as high as 33 to l have been attained without lubricant failure. It has further been observed that wear on the die has been considerably reduced and that the use of a lubricant in accordance with this invention results in an extruded metal product characterized by excellent surface characteristics.

The foregoing advantageous results have been obtained in accordance with this invention by coating metal billets prior to cold forming with a lubricating composition comprising an aqueous dispersion of a carboxylic polymethylene compound. The useful compounds are polymers characterized by high molecular weight, at least about 8,000, and by recurrence in the polymeric chain of -CH2 R- 0 I o l 0A units, wherein R is hydrogen or methyl and A is hydrogen or the ammonium radical. Such carboxylic polymethylene compounds result from the polymerization of acrylic acid or methacrylic acid, if desired in the presence of up to about 40% by weight of other ethylenic monomers such as vinyl acetate, vinyl stearate, vinyl myristate, vinyl palmitate, butadiene, alkyl esters of acrylic or methacrylic acid, for example the methyl, ethyl, propyl or butyl esters thereof, acrylonitrile or methacrylonitrile. Carboxylic polymethylenes may also be prepared by the polymerization of a monomer comprised predominantly of acrylonitrile or methacrylonitrile, or both, followed by hydrolysis of the nitrile side groups to carboxylic groups. Likewise, monomers comprised predominantly of lower alkyl acrylates or methacrylates may be polymerized and saponified.

The carboxylic polymethylene polymers referred to above are hydrophilic substances which swell in the presence of water and are dispersible therein to yield colloidal solutions of increased viscosity, characterized by pH values in the acid range, generally between 3 and 5. The aqueous dispersions react directly with metals such as aluminum, magnesium and iron, particularly at temperatures near the boiling point of water to form adherent water-insoluble carboxylates, the metal replacing one or .more hydrogens of the carboxyl groups of the carboxylic polymethylene. Similar derivatives of less active metals such as copper, lead, tin or silver result on reaction of the metal oxide with the carboxylic polymethylene.

Commercially available carboxylic polymethylenes, also termed carboxyvinyl polymers, which have been used successfully in accordance with this invention include the Carbopols (BF. Goodrich (30.), particularly Carbopol 934, polyacrylic acids and polymethacrylic acids, such as K702 (BF. Goodrich (30.), Tyze (Du Pont Co.) and Cyanamer 370 (American Cyanamid Co.).

It was found that aluminum billets after being cleaned by conventional methods, could be coated by dipping into a 25% by weight dispersion in Water of any of the above polymers. After air drying an adherent coating resulted and the billet was satisfactorily extruded. Previous attempts to perform such extrusion of billets coated with a single ingredient had always resulted in failure. For such coating, by a dipping or spraying process, the carboxylic polymethylene should be evenly dispersed in about four to twenty times its weight of solvent. Generally, lower extrusion pressures and improved surface of the extruded article result if the coated billet is baked for 30 to 60 minutes at a temperature of l"-l50 C. It is likewise generally advantageous to provide a carboxylic polymethylene including chain units derived by copolymerization with vinyl stearate or other similar long chain monomers or to provide additional lubricant and other desired ingredients in the coating composition.

A typical carboxylic polymethylene copolymer was prepared by mixing 4-0 grams of acrylic acid, in the form of a 30% solution in water, with 2 grams of polyvinyl alcohol, in the form of a solution in water, 20 grams of vinyl stearate and 0.2 gram of potassium persulfate. The exothermic polymerization reaction started at about 30 C., and the mixture was cooled to maintain the temperature at not above 90 C., at which temperature, the reaction was completed. Other known catalysts for this type of polymerization, such as benzoyl peroxide, and conventional wetting agents, as well as other variations in the reaction conditions, may be employed in such copolymerizations.

Particularly advantageous results have been obtained by coating the starting metal billet with a carboxylic polymethylene composition including additional lubricating agent, especially the higher fatty acids or Water-insoluble metal soaps or esters thereof. Suitable examples are stearic acid, Zinc stearate and lithium stearate. In general, such compounds have the formula (R COO),,R wherein n is an integer from 1 to 3; R is a monovalent organic radical containing at least seven carbon atoms in a straight or branched chain, which may include a by droxyl substituent and in which the carbon chain may be interrupted by an ether linkage; and R is a radical selected from the group consisting of hydrogen, a metal, and a saturated hydrocarbon group preferably containing 1 to 6 carbon atoms. The preferred metals are those forming water-insoluble compounds such as lithium and zinc.

At high reduction and surface expansion ratios the lubricating agent must be saturated to prevent stick-slip phenomena. Compounds wherein the total number of carbon atoms in the R group in the above formula is less than 7, are normally inoperative because of their volatility under the conditions of cold extrusion, the lack of an adequate soapy quality, and their general inability to act as a lubricant. As the reduction and surface expansion ratios are increased, the length of the chain in the lubricating agent must be increased, there being a direct relation between the length of the chain and its ability to act as a lubricant at increasing reduction ratios. While there is theoretically no upper limit to the number of carbon atoms suitable for use in the lubricating agent, practically speaking, compounds wherein R has more than 24 carbon atoms are difficult to obtain and the increased chain length above that point does not appreciably increase the lubricating ability of the compound.

Examples of compounds suitable for use as a lubricating agent are: caprylic, pelargonic capric, lauric, myristic, palmitic, phenylstearic, arachidic, behenic and stearic acids, the corresponding esters and the metallic salts thereof, hydroxystearic acid and similar hydroxy homologs of the acids, esters and salts named, Z-ethyl caprylic acid and similar branch-chain fatty acids, lanolin, beeswax and hydrogenated jojoba oil. Lanolin is a complex mixture of sterols and sterol esters, beeswax is a mixture of esters of long chain fatty acids and alcohols, and jojoba oil consists mainly of esters composed of C to C acids and alcohols.

In compositions including additional lubricant, as described above, reactant materials in addition to the carboxylic polymethylene are preferably included. Such reactant may for example consist of ammonia or certain substituted ammonia compounds, which react with active metals such as aluminum to form products which can then undergo double decomposition reaction with other coating bath constituents to form a bonded surface layer of metal soap. The ammoniacal compound also converts at least part of the carboxylic polymethylene to an ammonium or substituted ammonium salt, which, however, is capable of reacting with the metal billet surface to form the metal derivative.

The ammoniacal reactant consists of ammonia or a substituted ammonia such as an organic amine containing not more than six carbon atoms. While ammonia and ammonium hydroxide are preferred, other ammoniacal reactants which may be used are hydrazine, hydroxylamine, methylamine, ethylamine, isopropylamine, allylamine, benzylamine, mono-, di-, and triethanolamine, morpholine, pyridine, acetamide, propionamide, and aniline. Preferably, 1 to 15 parts by weight of ammoniacal reactant are used per parts by Weight of lubricating agent.

In addition to the lubricating agent and reactant, other ingredients may be used advantageously to effect specific purposes. Typically, the lubricating agent is suspended in a solvent. When an aqueous solution is used, wetting agents may be advantageously incorporated to disperse the insoluble lubricating agent in water. The viscosity of the composition may be controlled by the addition of suitable binders. To observe the thickness and completeness of the lubricant as applied to the metal billets, a dye may be advantageously used. Further, parting compounds may be included to prevent metal-to-metal contact. Also, since the lubricant is dipped, sprayed or painted onto the metal billet in relatively uneven amounts, a leveling compound may be used to cause the formation of a uniform level coat around the billet.

desirable, effective results are generally obtainable by increasing the proportion of this ingredient. Furthermore, it is advantageous to add the ammoniacal reactant last, whereby the viscosity is increased after the composition has been thoroughly mixed at much lower viscosities.

The wetting agents which may be incorporated in order to disperse the insoluble soaps, esters and fatty acids in water may be selected from a wide group of commercial compounds and such choice is determined by their chemical stability, their ability to keep the emulsion dispersed and to keep the tacky point above the operating temperature. Examples of such wetting agents are: a polyoxyalkylene derivative of sorbitan monostearate having a molecular weight of about 1300 (Tween 60, manufactured by Atlas Powder Co.), polyoxyethylene sorbitan monooleate (Tween 80, manufactured by Atlas Powder Co.), sorbitan monostearate (Span 60, manufactured by Atlas Powder Co.), sorbitan monooleate (Span 80, manufactured by Atlas Powder Co.), oxyethylene nonylphenol (Tergitol NPX, manufactured by Union Carbide (3., composition approximately one mole of oxyethylene per mole of monylphenol), polyoxyethylene nonylphenol (Tergitol NP14, manufactured by Union Carbide Co., composition approximately 14 moles of oxyethylene per mole of nonylphenol), polyoxyethylene nonylphenol (Tergitol NP35, manufactured by Union Carbide Co., composition approximately moles of oxyethylene per mole of nonylphenol), sulfated castor oil (manufactured by Baker Castor Oil Co.), alkyl aryl sulfonate (Duponol G, manufactured by Du Pont de Nemours & Co.), alkyl aryl sulfonate (Textilana MW, manufactured by Textilana C-orp.), polyoxypropylene glycol (Pluronic L 62, manufactured by Wyandotte Chemicals Corp), and fatty alkanolamides (Emcol 5100T, manufactured by Witco Chemical Co.). Other similar wetting agents may be used.

Binders suitable for use to control the viscosity of the lubricant are materials such as gum tragacanth, starch, dextrine, casein, and glue. Other similar thixotropic materials may be used. While the use of a dye is not essential to the lubricant, it may be used advantageously for at least two purposes, first, the final lubricant in the thickness used is transparent and the inclusion of a dye provides a visible film, the relative thickness of which can be judged by the intensity of the color; secondly, if the dye chosen acts as a pH indicator, the evolution of ammonia during the curing operation can be readily followed by the change in color. Oil soluble dyes and other dyes which do not participate in the reaction may be used.

Parting compounds well known in the extrusion art to prevent metal-to-metal contact may also be included. Examples of such compounds are talc, mica, graphite, chalk, borax, lithopone, zinc oxide, white lead and poly hydric alcohol esters of bentonite (Bentones, manufactured by National Lead Company).

As indicated above, in order to achieve a uniform thickness, leveling compounds may be added to the cold extrusion lubricant to eliminate brush strokes and to provide a smooth and level surface. It has been determined that ammonium hydroxide makes the lubricant self-leveling. However, if other ammoniacal compounds are used as the reactant, such compounds as carboxymethylcellulose, tricresyl phosphate, glycerine, lecithin, ethylene glycol and sorbitan borate tend to make the lubricant self-leveling.

While water is the preferred solvent in forming the coating emulsion, other volatile solvents which do not react with the metal billet or enter into unfavorable side reactions with the other constituents may be added. Examples of such solvents are acetone, methylethylketone methyl, ethyl, and isopropyl alcohols and kerosene.

The relative proportions of the various constituents included in the cold extrusion lubricant may be varied over a wide range and depend, to a large extent, on the reactivity of the particular metal to be extruded, the pH of the lubricant, the reduction and surface expansion ratio desired and the lubricating qualities of the fatty acids or derivaties thereof used. Based on 100 parts by weight of total lubricating agent, the following indicates satisfactory by weight ranges for the additional constituents which may be advantageously used in the composi tion:

Maximum, Minimum,

parts part Wetting agent 5 V2 Binder 5 Parting compoun 30 i u Leveling compound. 5 M o be used advantageously include any metal to which the cold extrusion process is commercially practicable, provided the indicated reactions can occur. such metals are aluminum, iron, copper, lead, silver, magnesium and the alloys thereof. By the use of the lubricating compositions in accordance with this invention, reduction and surface expanding ratios from 5 to l to 33 to l have been readily achieved.

In order to achieve the chemical bond indicated above, it is necessary that the metal billet be chemically clean. The cleaning can be accomplished by etching, the use of suitable solvents, preceded if desired by sandblast ing. The chemically clean surface is essential for application of the lubricant or billets where the surface expansion is large. In cases of relatively small surface expansion, sufficient reaction takes place to maintain the adhesion of the lubricant even without preliminary cleanmg.

The lubricant may be applied by any of the standard methods of paint application including dipping or spraying. It is desirable to obtain a uniform coat of controlled thickness. The coating weight will vary according to the material and type of extrusion and may be in the range of from 1 to 200 milligrams per square foot.

In order to obtain a smooth, hard coat which will adhere to the billet, the coated billet is heated above the melting point of the lubricant. The temperature is, there fore, dependent on the choice of lubricating agent and may be varied from about 200 C. to 250 C. The heat-- ing time required depends on the heat capacity and surface to volume ratios of the billet, the heating being continued until the reaction is complete. The heated billet is usually tacky, or sticky, and it is then necessary to cool the billet below the tacky point prior to handling.

The above indicated process of forming a coated billet, using the cold extrusion lubricant provides a billet having a slippery, smooth, coat of lubricant which adheres firmly, through chemical reaction, to the metal. However, metal billets coated with the present compositions have been air dried without heating to elevated temperatures and were successfully extruded.

The following specific examples are illustrative of lubricant coating compositions in accordance with this invention which have been applied to metal billets which were successfully extruded. In the following examples, it will be seen that the content of carboxylic polymethylene ingredient was in the ratio of about 1 to 44 parts per parts by weight of the lubricating agent.

Examples of Table I Oarb'oxylic Total Other Other Example Poly- Water, Lubricating Ingredients,

methylene, gals. Agent, lbs.

lbs. lbs.

25 10 900 in stearate... 10 1, 530 160 Zinc stearate. 0.5 dyo.

5 1,000 05 Zinc stoarato 1 gum tragaeanth. 10 1,000 Zinc stearate" 1 gum tragacanth. 15 1,000 85 zinc stearatec. 1 gum tragacanth. 20 1,000 80 Zinc stearate" 1 gum tragaoanth. 15 425 85 Zinc stearata. 1, 135 42, 400 6,400 zinc 19 dye.

stearate. O 1, 800 150 Zinc 0.5 dye.

stearate. 9 174 21 vinyl 0.1 dye, 0.3 Span stearate. 60, 0.3 Tween 60. 7 90 22 polyvinyl 0.05 dye. stearate. 24 700 112.5 vinyl 0.3 dye, 1 polystearate. vinyl alcohol,

1.2 Span 60, 1.2 Tween 60. 14 6. 75 25. 5 14.2 Zinc 0.11 dye stearate; 21.2 lithium stoarate. 15 Copoly- 150 2 polyvinyl rneralcohol, 4 ized Torgitol NP 40 acry- 35, 1.5 lie acid, Tween 20. 20 vinyl stearate In the above examples, the carboxylic polymethylene consisted ofpolyacrylic acid unless otherwise indicated. Generally, commercially available material was used, such as K702 (Goodrich) or Cyanamer 370 (American Cyanamid), duplicate runs of several examples using different polyacrylic acids yielding essentially similar successful results. The numbers in the table represent parts by weight unless otherwise indicated.

In mixing the compositions, it is preferable to disperse each ingredient in a portion of the water used and to mix these dispersions together with thorough agitation. Advantageously, the mixture is homogenized for a period of 30 to 60 minutes by means of a conventional colloid mill, particularly when the coating is to be applied by spraying.

In the examples includinga dye, any compatible dye such as oil soluble green N0. 3126 could be used effectively. Generally, the coatings are sprayed uniformly over the metal billets at room temperature, although dipping, brushing. or roller coating methods are likewise applicable. The coated billets were air dried at room temperature and were found to extrude successfully. However, an improved surface of the extruded article was generally obtained by baking the air-dried coated billets for 30-90 minutes at a temperature of about 100 C. to 150 C.

. In compositions including a metal stearate ingredient, it was found that part or all of the carboxylic polymethylene of the initial composition could be replaced by monomeric acrylic acid or methacrylic acid, as the polymerization thereof appeared to be catalyzed and proceed during the mixing and subsequent coating and drying operations. Similarly, copolymers of acrylic or methacrylic acid with monomers such as vinyl stearate were formed during the mixing and subsequent operations, resulting in coated billets of exceptionally low coefficient of friction.

Successful extrusion tests of the coated billets included the extrusion of hollow billets of varied dimensions to produce lengths of pipe, of solid billets to produce rod and of discs to yield elongated cups. For example, hol- -1ow aluminum cylindrical billets 23% inches in length and having internal diameter of 4.97 inches and external diameter of 6.51 inches were coated and extruded to yield pipe 32 feet long, 5 inches in outside diameter and having an average wall thickness of 0.045 inch, the re- 8. duction and surface ratio being approximately 20 to 1 in this extrusion.

The following examples are illustrative lubricantcompositions including an ammoniacal reactant in addition to the carboxylic polymethylene.

Table II Carboxylic Water, Lubricating Example Polymeth gallons Agent Other Ingredients ylene, lbs.

16 4 3,600 20 stearic acid, 1 dye, 4 Span- 152 zinc stea 60,? 4 Tween rate, 228 lithium 60, 40 ammonia. stearate.

17 0.3 270 1.5 stearic acid, 0.3 Span 60,"

11.4 zine stea- 0.3 Tween 60, rate, 17.1 lith- 48 ammonia. ium stearate.

l8 0.3 180 1.5 stearic acid, 0.1 dye, 0.3 Span 28.5 vinyl stea- 60 0.3 Tween rate. 00, 4.8 ammon- 19 0. 5 145 23.3 polyvinly 0.05 dye,

stearato. 17 ammonia.

20 0. 25 50 12.3 polyvinly 0.1 dye,

stearate. 2 ammonia.

21 0.3 180 1.5 stearlo acid, 0.1 dye,

28.5 polyvinyl 0.3 Span 60, stearate. 0.3 Tween 60,"

4.8 ammonia.

22 0. 44 50 2.2 lbs. stearic 0.11 lbs. dye, 0.44 acid, 16.8 lbs. lbs. Span 60, zinc steal-ate, 0.44 lbs. Tween 25.2 lbs. lithium 60, 7.04 lbs. stearate. ammonia.

In Table II,- the figures refer to parts by weight unless otherwise indicated. The carboxylic polymethylene represents a carboxyvinyl homopolymer such as polyacrylic acid or poly-methacrylic acid or a vinyl copolymer consisting predominately of carboxyvinyl units such as Carbopol 934 or 1 (Goodrich). Ammonia referred to in the table consisted of 28% by weight aqueous solution of ammonium hydroxide and was preferably added to the composition after thorough mixing and homogenizing of the other ingredients.

Mixing and treating procedures were as described above with respect to the examples of Table I. However, all the coated billets were subjected to baking at about C. to 250 C. for 30 to 90 minutes after air drying, baking temperatures of about C. being preferred.

As in the case of the examples under Table I, successful extrusions were carried out on metal billets, both solidand hollow, to form rods, tubes, and pipes displaying excellent surface finish and characterized by desirable physical properties; Extrusions characterized by reduction and surface ratio of from 5 to 1 to as high as 33 to 1 were successfully performed. The lubricant coating in accordance with this invention is applicable to facilitating the extrusion of aluminum and its alloys, iron, copper, brass,- magnesium, lead, tin and silver, as well as other malleable metals. Also, the coating compositions in accordance with this invention are effective in facilitating other cold deformation procedures, such as cold rolling, used in fabricating metal articles.

What is claimed as new and is desired to be covered 'by Letters Patent is as follows:

1. A method of applying an adherent lubricant coating to a metal article comprising applyingto said article a uniform coating of a 5 to 20% by weight aqueousdis? persion of lubricating agent, said dispersion. containing as an essential ingredient a carboxylic polymethylene in a ratio of about 1 to 44 partsper 100 parts by weight of said lubricating agent, and evaporating the volatile constituents of the said coating, said lubricating agent having the formula (R COO) R wherein n is an integer from '1 to 3, R is a monovalent hydrocarbon radical having at least 7 carbon atoms and R is a radical selected from the group consisting of hydrogen, a metal, and a monovalent hydrocarbon group.

2. A method in accordance with claim 1, wherein said carboxylic polymethylene is polyacrylic acid.

3. A method in accordance with claim 1, wherein said carboxylic polymethylene is polymethacrylic acid.

4. A method in accordance with claim 1, wherein said carboxylic polymethylene is a vinyl polymer containing predominantly carboxyvinyl units.

5. A method of applying an adherent lubricant coating to a metal article comprising applying to said article a. uniform coating of a to 20% by weight aqueous dispersion of a water-insoluble metal soap, said dispersion containing as an essential ingredient a carboxylic polymethylene in a ratio of about 1 to 44 parts per 100 parts by weight of said soap, and evaporating the volatile constituents of said coating.

6. A coated metal article comprising a metal base and a thin lubricant film covering the surface thereof, said film weighing up to about 200 milligrams per square foot and containing as essential ingredients a carboxylic polymethylene polymer and a compound having the formula (R COO),,R wherein n is an integer from 1 to 3, R is a monovalent hydrocarbon radical. having at least 7 carbon atoms and R is a radical selected from the group consisting of hydrogen, a metal, and a monovalent hydro carbon group, in a ratio of about 1 to 44 parts of said polymer per 100 parts by weight of said compound.

7. A lubricant composition for use in the cold forming of metals consisting essentially of a car-boxylic polymethylene, a lubricating agent and an aqueous solvent, said lubricating agent having the formula wherein n is an integer from 1 to 3, R is a monovalent hydrocarbon radical having at least 7 carbon atoms and R is a radical selected from the group consisting of hydrogen, a metal and a monovalent hydrocarbon radical, said ingredients being present in the ratio of about 400 to 2000 parts by weight of solvent and about 1 to 44 parts of carboxylic polymethylene per 100 total parts by weight of said lubricating agent.

8. A lubricant composition for use in the cold forming of metals consisting essentially of a carboxylic polymethylene, a lubricating agent, an ammoniacal reactant selected from the group consisting of ammonia, hydra- 10 zine, hydroxylamine and organic amines containing not more than six carbon atoms and an aqueous solvent, said lubricating agent having the formula wherein n is an integer from 1 to 3, R is a monovalent hydrocarbon radical having at least 7 carbon atoms and R is a radical selected from the group consisting of hydrogen, a metal and a monovalent hydrocarbon radical, said ingredients being present in a ratio of about 1 to 15 parts of reactant, 1 to 44 parts of carboxylic polymethylene and 400 to 2000 parts of said solvent per parts by Weight of said lubricating agent.

9. A lubricant composition for use in the cold forming of metals consisting essentially of a carboxylic polymethylene, a Water-insoluble soap of a higher fatty acid and an aqueous solvent, said ingredients being present in the ratio of about 400 to 2000 par-ts by Weight of said solvent and 1 to 44 parts of carboxylic polymethylene per 100 parts by weight of the said derivative.

10. A lubricating composition for use in the cold forming of metals consisting essentially of a carboxylic polymethylene, a water-insoluble soap of a higher fatty acid, an ammoniacal reactant selected from the group consisting of ammonia, hydrazine, hydroxylamine and or ganic amines containing not more than 6 carbon atoms, and an aqueous solvent, said ingredients being present in the ratio of 1 to 15 parts of said reactant, 1 to 44 parts of said carboxylic polymethylene, and 400 to 2000 parts of said solvent per 100 parts by weight of said derivative.

References Cited in the file of this patent UNITED STATES PATENTS 2,588,234 Henricks Mar. 4, 1952 2,703,768 Hall Mar. 8, 1955 2,767,111 Otto et al. Oct. 16, 1956 2,865,877 Hatton et a1. Dec. 23, 1958 2,874,080 Schweitzer et al. Feb. 17, 1959 2,902,390 Bell Sept. 1, 1959 FOREIGN PATENTS 871,239 Germany Mar. 19, 1953 

1. A METHOD OF APPLYING AN ADHERENT LUBRICANT COATING TO A METAL ARTICLE COMPRISING APPLYING TO SAID ARTICLE A UNIFORM COATING OF A 5 TO 20% BY WEIGHT AQUEOUS DISPERSION OF LUBRICATING AGENT, SAID DISPERSION CONTAINING AS AN ESSENTIAL INGREDIENT A CARBOXYLIC POLYMETHYLENE IN A RATIO OF ABOUT 1 TO 44 PARTS PER 100 PARTS BY WEIGHT OF SAID LUBRICATING AGENT, AND EVAPORATING THE VOLATILE CONSTITUENTS OF THE SAID COATING, SAID LUBRICATING AGENT HAVING THE FORMULA (R1COO)NR2, WHEREIN N IS AN INTEGER FROM 1 TO 3, R1 IS A MONOVALENT HYDROCARBON RADICAL HAVING AT LEAST 7 CARBON ATOMS AND R2 IS A RADICAL SELECTED FROM THE GROUP CONSISTING OF HYDROGEN, A METAL, AND A MONOVALENT HYDROCARBON GROUP. 